City and/or district transport line

ABSTRACT

The present invention relates to an improved city and/or district transport line, particularly for passengers, comprising a continuous travel track running without interruptions between two terminal stations of the line, at least one halt track section associated with an intermediate station of the line, a plurality of self-propelled cars movable along said travel track and said halt track sections, and transferring means allowing to transfer the cars from the travel track to the halt tracks or vice versa, said transferring means comprising at least two sections of shunting tracks, said shunting track sections connecting the ends of each halt track section to the travel track, each car being provided with first rolling means for its advancement along the travel track and along the halt track, and with second rolling means for advancement along the shunting tracks.

[111 3,906,863 [451 Sept. 23, 1975 1 1 CITY AND/OR DISTRICT TRANSPORT LINE [76] Inventor: Riccardo Baldelli,Viale Mantegazza, 24, Rimini (Forli), Italy, 47037 [22] Filed: Feb. 22, 1973 [21] Appl. No.: 334,608

[56] References Cited UNITED STATES PATENTS 3,590,743 7/1971 Larson 104/130 3,595,173 7/1971 Giraud... 104/23 FS 3,626,857 12/1971 Omar 104/130 Primary Examiner-M. Henson Wood, Jr.

Assistant Examiner-D. W. Keen Attorney, Agent, or Firm-Burns, Doane, Swecker & Mathis [57] ABSTRACT The present invention relates to an improved city and- /or district transport line, particularly for passengers, comprising a continuous travel track running without interruptions between two terminal stations of the line, at least one halt track section associated with an intermediate station of the line, a plurality of selfpropelled cars movable along said travel track and said halt track sections, and transferring means allowing to transfer the cars from the travel track to the halt tracks or vice versa, said transferring means com prising at least two sections of shunting tracks, said shunting track sections connecting the ends of each halt track section to the travel track, each car being provided with first rolling means for its advancement along the travel track and along the halt track, and with second rolling means for advancement along the shunting tracks.

17 Claims, 10 Drawing Figures US Patnt Sept. 23,1975 Sheet 1 of5 3,906,863

US Patent Sept. 23,1975 Sheet 2 of5 3,906,863

US Patent Sept. 23,1975 Sheet 3 of5 3,906,863

FIG. 5.

US Patent Sept. 23,1975 Shet4 0f5 3,906,863

US Patent Sept. 23,1975 shw 5 of5 3,906,863

BACKGROUND OF THE INVENTION 1. Field of the Invention Y The present invention relates to a city and/or district transport line in which use is preferably made of small self-propelled cars or units, arranged to carry a limited number of passengers.

2. Description of the Prior Art A transport line of this type has already been'described in the Italian Pat. No. 829,688 dated Apr. 2, 1968, in the name of the same applicant. This transport line is based on the main concept of using a continuous track i.e., without interruptions and without switches running between the two terminal stations of the line, a series of halt tracks associated with the intermediate stations, and cars provided with two distinct sets of drive means, of which a first set permits advancement along the continuous travel track and the second set is operated in the proximity of the halt tracks leading to the intermediate stations, to permit the car to pass from the travel track to the halt track and to advance along this latter.

Although this general idea and the means allowing to put it into practise have proved to be of considerable interest, the need has been felt to study, as far as possible, the simplifying of the structure and operation.

SUMMARY OF THE INVENTION The object of the present invention is consequently an improved transport line structure, the basic concept of which consists essentially of the fact that it comprises a continuous travel track running between two terminal stations of the line, at least one halt track section associated with an intermediate station of the line, at least two sections of shunting tracks which enable the ends of the halt track to be connected to the travel track, and at least one car provided withfirst rolling means for its advancement along the travel track and halt track, and second rolling means which permit movement along said shunting tracks. I

The main advantage of the structure heretofore described consists of a simplification of the control means for the car. In fact, in the aforementioned Italian Pat. No. 829,688, control and operating means must be associated with each car for moving it along the travel track, together with further control and operating means for moving the car along the halt track. In the case of the structure according to the present invention, only one set of control and operating means is instead required for moving the car along the travel track and along the halt track, While the rolling means for movement along the shunting tracks may, because of the short length of the latter, be simple constant speed drive means. I

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the structure according to the presentinvention are more fully described hereinafter, with reference to some preferred:

embodiments given by way of example and illustrated in the accompanying drawings, in which:

FIG. I is a diagrammatic perspective view of a short section of travel or halt track;

FIG. 2 is a diagrammatic cross-section of a car according to the invention;

FIG 3 is a diagrammatic longitudinal section ofa car, with parts visible; FIG. 4 is a diagrammatic view of the hydraulic control assembly fo'r the upper bogie of the car;

FIGS. 5 and 6 are two different shunting track arrangements;

FIG. 7 is a diagrammatic view of the connection zone between the shunting track and travel track;

FIG. 8 is a further arrangement of the shunting track;

FIGS. 9 and 10 show a particular switching device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, both the travel and halt tracks comprise a pair of base rails 1 and 2 shaped substantially in the form of an L; in practice, according to one characteristic of the present invention and taking into consideration the use of cars with pneumatic-tired wheels, the base rails must comprise an upper horizontal surface A for supporting the driving wheels, and a vertical surface B against which the guiding wheels rest. The most simple structure for the rails 1 and 2 is hence an L-section, but it is obvious that other sections may be used, for example C or H or the like, according to the structural requirements of the line.

The track further comprises a pair of guide rails 3 and 4 disposed above the rails l and 2 and at a level higher than the centre of gravity of the cars. The rails 3 and 4 must also be of L-section or the like, for the purpose described hereinafter.

The rails l and 3, as well as the rails 2 and 4 may be joined one to the other by stiffening trellises 5, or be rendered mutually integral by any other suitable means.

The short section of track shown, in FIG. 1 is mounted on columns 6, the tops of which are shaped as a fork. However, the track may also befixed directly to the ground with modifications within the capability of any expert of the art.

An example of a car which may be used in the present invention is shown diagrammatically in FIGS. 2 and 3. It comprises a body with a limited number of seats 7 for example eight seats arranged in pairs and a motor compartment 8 to the rear. The seats however may be of any number, starting from a single seat.

The car is mounted on four main wheels 9 and 10, of which at least the rear wheels 10 are driven by an electric motor M. The car further comprises a set of lateral wheels, mounted on vertical pivots, which guide and retain the car laterally along thetrack, and particularly around bends. These comprise wheels 11 and 12, close to the base and arranged to rest against the sides of the rails l and 2, and wheels 13 and 14, preferably close to the top of the car and arranged to rest against the side of the guide rails 3 and 4.

The main purpose of the upper wheels 13 and 14 is to retain the car around bends. As they rest in a position at a level above the centre of gravity of the car, their operation is perfectly safe.

According to an important characteristic of the present invention, the car is also provided with four support wheels 15 and 16 mounted on horizontal pivots and arranged close to the top of the car. These are apt to rest on the upper surface of the rails 3 and 4, under the con ditions which will be described hereinafter by way of example.

The wheels 15, 16 are mounted on pivots 15a, 16a respectively, which form part of a hydraulic jack assembly better shown in FIG. 4. This assembly consists of a pair of coaxial opposing cylinders l7, 18, joined together at the centre of the car by way of a chamber 19 of fluid under pressure. Coaxial to the cylinders -17, I8 is provided a guide rod 210 along which pistons 21 and 22 slide by virtue of the pressure of the fluid contained in the chamber 19 and in the cylinders l7, 18. These pistons 21, 22, in turn carry the pivots 15a and 16a (not shown in FIG. 4) of the wheels 15 and 16. It is possible, by means'of a control system of known type and consequently not shown, to impart axial symmetrical movements to the pistons 21 and 22 which move the wheels 15 and 16 from a rest position, shown by the dotted lines in FIG. 2 and in which the wheels do not project beyond the line of the side walls of the car, to a working position, shown by the full lines in FIG. 2, and in which the wheels project from the sides of the car beyond the vertical plane ,of tangency of the side wheels 11, 12, 13 and 14. In their working position, the wheels 15 and 16 are consequently arranged to rest on the upper horizontal surface of the rails 3 and 4.

As stated, the travel track has a structure which is substantially identical to the halt track. Shunting tracks, better shown in FIGS. 5 and 6, are provided for passage from one track to the other. These shunting tracks consist essentially of sections 3 and 4 of the only guide rails 3 and 4, and the switching zone better shown in FIG. 7 has no moving parts, but is simply the very section of rail 4 (or 3) which connects smoothly and stably to the rail 4.

When a car travels along the travel rail without the need for deviation, its wheels 910 follow the path T along the base rail 2, the wheels 11-12 follow the path T along the same base rail 2, and the wheels 13-14 follow the path T along the guide rail 4, while the shunting rail 4 offers no obstacle. Under these conditions, the wheels 15 and 16 are completely retracted into the side of the car (rest position indicated by dashed lines in FIG. 2).

When a car is to be deviated towards a halt track, its wheels 15 and 16 are moved outwards to the working position shown by the full lines in FIG. 2. When the wheels 15, 16 are extracted, they follow the path R on the upper surface of the rail 4. This path R, when it reaches the point S of connection between rail 4 and rail 4, must obviously follow this latter. The car is thus driven along the rail 4 and raised from the rail 2. The wheels 13-14 now follow the path R, the wheels 11-12 follow the path R", and the wheels 9-10, starting from the point S, move away from the travel track. In the connecting position shown in FIG. 7, the lateral wall of the rail 2 is connected in a continuous way to the lateral' wall of the rail 4, through the plate 2a, so as to allow the wheels 11-12 to follow a continuous path up to the point S, without having to go through a trellis zone; starting from the point S also the wheels 1112 move away from the travel track.

The shunting track 34 has a length-which is just sufficient to enable the car travelling along it to be raised and separated completely from the travel track C and to reach the halt track F. This latter may be disposed above the travel track and suitably spaced from it, as shown in FIG. 5, or it may be on the same level, but deviated angularly from the travel track, as shown in FIG. 6. In this latter case the shunting track must follow an initial upward path in order to raise the car from the travel track, and then a downward path to bring the car towards the halt track.

Arrangements other than these two embodiments are evidently'possible, which may take account of the configuration of the vground and the availability of space.

lt should anyhow be noted that if the car has to follow an upward path when it approached and enters the shunting track, its mere inertia will generally not be sufficient to .enable it to reach the halt track, whereby drive means must be provided, also in association with the wheels 15, 16, so asto guarantee the advancement. As stated heretofore, it is not necessary for said drive means to be controlled by complicated control means, it being sufficient toprovide a switch which gives a constant, even minimum speed, of movement.

However, a modification would consist of the arrangement shown in FIG. 8. In this embodiment the travel track C, in the zone of connection with the shunting track, follows a downward path. This enables the shunting track 3' 4' to be'disposed horizontally or even slightly sloping. In this case the wheels 15 and 16 may be idle wheels and the car, once it has been shunted on to the shunting track, can proceed to the successive halt track by mere inertia- It is evident from thedrawing that, even in this case, the required raising of the car from the travel track is ensured.

As stated heretofore, the structure of the halt track comprises pairs of guide rails 12 and 3-4, similarly to the travel track, for at least the first part of its length, i.e., in practice, from the initial position where it joins the shunting track to its entry into the station. However, at the entry into the station, the speed of the cars is so low that the safety provided by the upper rails 3 and 4 is no longer necessary. Thus, in the station, the track consists preferably of only thelower rails 1 and 2. However, as a plurality of departure and arrival service track sections are provided within the confines of the station, switching devices must be provided for mutually connecting these tracks. Taking into account the fact that, as stated initially, the cars used in the invention are preferably of the tired-wheel type, the switching device is constructed in the manner shown in FIGS. 9 and 10. As shown, in' the switching zone between the arrival track BR and two departure tracks BS and BC), the vertical flange B of the rail 1 has a continuous straight shape and connects the track BR to the track BS. The vertical flange B of the rail 2 however has a continuous curved shape and connectes the track BR to the track HQ. The rail 1 of the track B0 and the rail 2 of the track BS'are finally joined with a sharp corner at V.

The switching zone also comprises two horizontal rolling surfaces 20 and 21 respectively, which form an extension of the horizontal flange of the rails 1 and 2, on the curved section Y. V and the straight section XV respectively. Together with these rolling surfaces 20 and 21 are also provided two lateral guides 22 and 23 respectively, which form 'an' extension of the vertical flanges of the rails 1 and 2, along the same sections YV- and X'V respectively. The rolling surfaces 20 and 21 are fixed, whereas the vertical lateral guides 22 and 23 may be moved vertically by the jack system shown diagrammatically in FIG.' 10. As shown, each lateral guide can move betweena first extracted working posi tion, shown by full lines in FIG. '10, in which the vertical flange 22 (or 23) projects above the horizontal plane, formed by the flange of the rail 1 and by the surface (or 21), by a length sufficient to form an extension of the flange B of the rail 1, at the connecting point between track BR and track HQ, and a second retracted or rest position, indicated by dotted lines in FIG. 10, in which the upper edge of the flange 22 disappears below the surface A-20. It is evident that when the guide 22 is extracted, the guide 23 is retracted and vice versa, In the first case a continuity of the track BR-BQ is achieved, whereas in the second case, i.e., when the guide 22 is retractedand the guide 23 extracted, a continuity of the tracks BR-BS is obtained.

Although a preferred embodiment of the present invention has been heretofore described, various different embodiments are possible without leaving the scope of the invention.

I claim: 1. A city and/or district transport line particularly for passengers, comprising:

a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one section of shunting track connecting each halt track to the travel track; a car movable along the travel, halt, and shunting tracks; first rolling means for the advancement of the car along the travel and halt tracks, said first rolling means being comprised of a first set of driven wheels rotatable about horizontal axes to support and advance the car; and laterally projectable second rolling means for advancing the car along the shunting track to transfer the car between the travel track and-the halt track, said second rolling means being comprised ofa second set of wheels including a pair of front wheels and a pair of rear wheels each rotatable about a horizontal axis and laterally movable between a retracted, rest position not projecting substantially beyond the lateral profile of the car and an ex tended, working position in engagement with the shunting track.

2. A city and or district transport line particularly for passengers comprising:

a continuous travel track running without interruption between two terminal stations of the line;

at least one halt track associated with an intermediate station of the line;

at least one shunting track connecting the halt track to the travel track;

at least one car movable along the travel track and the halt track;

power driven rolling means, carried by the car at a first vertical level thereof, for moving the car along the travel and halt tracks and for controlling the rate of movement of the car therealong; and

second rolling means carried by the car at a second vertical level thereof for engaging the shunting track to advance the car therealong and transfer the car from the travel track to the halt track of the intermediate station, the second rolling means being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track;

said travel track and halt track each comprising a pair of main rails, each rail having an L-shaped sec tion, the horizontal flange thereof projecting from a lower portion of the vertical flange thereof toward the inside of the track to engage the first rolling means and support the car, and the vertical flange of the L-section serving to guide the car.

3. A transport line as defined in claim 2 wherein the travel track further comprises:

a pair of secondary rails, each secondary rail having at least a vertical guiding flange, aligned in the same plane as the vertical flange of one of said main rails, and a horizontal support flange projecting from said vertical flange toward the outside of the track.

4. A transport line as defined in claim 3, wherein:

said pair of secondary rails is positioned at a level higher than the level of the centre of gravity of a car traveling along the line.

5. A transport line as defined in claim 4 wherein each shunting track comprises:

a length of a pair of secondary rails gradually interconnecting the secondary rails of the travel track.

6. A transport line as defined in claim 2 wherein:

said halt track is comprised. of at least one switch for switching a car from the halt track to one of at least two like service tracks, said switch including substantially continuous, fixed, horizontal support and rolling flanges, and at least two vertical, alternately operable guiding flanges, said support and rolling flanges forming a continuous connection between the horizontal flanges of the main rails of the halt and service tracks, and said two vertical flanges forming continuous connections alternately with one or the other of the connected service tracks.

7. A transport line as defined in claim 6 wherein:

said vertical guiding flanges are movable vertically between an extracted working position wherein a connection is formed between the vertical flanges of the main rails, and a retracted, rest position, beneath the horizontal plane of the support and rolling flanges.

8. A city and/or district transport line particularly for passengers comprising:

a continuous travel track running without interruption between two terminal stations of the line;

at least one halt track associated with an intermediate station of the line;

at least one shunting track connecting the halt track to the travel track;

at least one car movable along the travel track and the halt track;

first rolling means, carried by the car at a first vertical level thereof, for moving the car along the travel and halt tracks and for controlling the rate of movement of the car therealong, said first rolling means comprising:

a first set of wheels rotatable on horizontal axes, said first set of wheels supporting the car on the travel and halt tracks and having driving means for advancing the car therealong, and

a second set of wheels rotatable about vertical axes, said second set of wheels forming guiding means for guiding movement of the car along said travel and halt tracks; and

second rolling means, carried by the car at a second vertical level thereof for engaging the shunting track to advance the car therealong and transfer the car from the travel track to the halt track of the intermediate station, the second rolling means being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track; said second rolling means comprising a third set of wheels rotatable about horizontal axes, said third set of wheels being engageable with a shunting track to advance the car between the travel and halt tracks.

9. A transport line as defined in claim 8 wherein each car further comprises:

a fourth set of wheels rotatable about vertical axes, said fourth set of Wheels forming guiding means for guiding the car along the travel, halt, and shunting tracks.

10. A city and/or district transport line particularly for passengers, comprising:

a continuous travel track running without interruption between two terminal stations of the line;

at least one halt track associated with an intermediate station of the line;

at least one shunting track connecting the halt track to the travel track;

at least one self-propelled car movable along the travel track and the halt track;

a first set of wheels, carried by the car at a first vertical level thereof for supporting said car on said travel and halt tracks;

controllable motor means on said car for driving the wheels of said first set to move the car along the travel and halt tracks and to control the rate of movement of the car therealong; and

a second set of wheels, carried by the car at a second vertical level thereof for engaging the shunting track to rollingly support the car thereon and transfer the car from the travel track to the halt track of the intermediate station, the last mentioned wheels being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track.

11. A transport line as defined in claim 10 wherein:

said shunting track slopes in a generally downward manner from connection with said travel track to connection with said halt track.

12. A transport line as defined in claim 10 further comprising:

5 for passengers, comprising:

a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one section of shunting track connecting each halt track to the travel track; at least one car movable along the travel, halt, and

shunting tracks; first rolling means for the advancement of the car along the travel and halt tracks, said first rolling means being comprised of a first set of driven wheels rotatable about horizontal axes to support and advance the car, and a second set of wheels rotatable about vertical axes to guide the car, and second rolling means for advancing the car along the shunting track to transfer the car between the travel track and the halt track, said second rolling means being comprised of a third set of wheels including a pair of front wheels and a pair of rear wheels each rotatable about a horizontal axis and movable between a retracted, rest position not projecting beyond the lateral profile of the car and an extended, working position in engagement with the shunting track. 14. A transport line as defined in claim 13 wherein: said third set of wheels is associated with a hydraulic control system for controlling the retraction and extension of the wheels. 15. A transport line as defined in claim 13 wherein: the wheels of said third set idle about their respective axes, each car advancing by inertia along said shunting track. 16. A transport line as defined in claim 15 wherein: each shunting track is arranged in a slightly descending path, the section of travel track lying beneath said shunting track being in turn arranged in a descending path of greater slope. 17. A transport line as defined in claim 13 wherein: the wheels of said third set of wheels are driven through a transmission system operably associated with the first rolling means. 

1. A city and/or district transport line particularly for passengers, comprising: a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one section of shunting track connecting each halt track to the travel track; a car movable along the travel, halt, and shunting tracks; first rolling means for the advancement of the car along the travel and halt tracks, said first rolling means being comprised of a first set of driven wheels rotatable about horizontal axes to support and advance the car; and laterally projectable second rolling means for advancing the car along the shunting track to transfer the car between the travel track and the halt track, said second rolling means being comprised of a second set of wheels including a pair of front wheels and a pair of rear wheels each rotatable about a horizontal axis and laterally movable between a retracted, rest position not projecting substantially beyond the lateral profile of the car and an extended, working position in engagement with the shunting track.
 2. A city and or district transport line particularly for passengers comprising: a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one shunting track connecting the halt track to the travel track; at least one car movable along the travel track and the halt track; power driven rolling means, carried by the car at a first vertical level thereof, for moving the car along the travel and halt tracks and for controlling the rate of movement of the car therealong; and second rolling means carried by the car at a second vertical level thereof for engaging the shunting track to advance the car therealong and transfer the car from the travel track to the halt track of the intermediate station, the second rolling means being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track; said travel track and halt track each comprising a pair of main rails, each rail having an L-shaped section, the horizontal flange thereof projecting from a lower portion of the vertical flange thereof toward the inside of the track to engage the first rolling means and support the car, and the vertical flange of the L-section serving to guide the car.
 3. A transport line as defined in claim 2 wherein the travel track further comprises: a pair of secondary rails, each secondary rail having at least a vertical guiding flange, aligned in the same plane as the vertical flange of one of said main rails, and a horizontal support flange projecting from said vertical flange toward the outside of the track.
 4. A transport line as defined in claim 3, wherein: said pair of secondary rails is positioned at a level higher than the level of the centre of gravity of a car traveling along the line.
 5. A transport line as defined in claim 4 wherein each shunting track comprises: a length of a pair of secondary rails gradually interconnecting the secondary rails of the travel track.
 6. A transport line as defined in claim 2 wherein: said halt track is comprised of at least one switch for switching a car from the halt track to one of at least two like service tracks, said switch including substantially continuous, fixed, horizontal support and rolling flanges, and at least two vertical, alternately operable guiding flanges, said support and rolling flanges forming a continuous connection between the horizontal flanges of the main rails of the halt and service tracks, and said two vertical flanges forming continuous connections alternately with one or the other of the connected service tracks.
 7. A transport line as defined in claim 6 wherein: said vertical guiding flanges are movable vertically between an extracted working position wherein a connection is formed between the vertical flanges of the main rails, and a retracted, rest position, beneath the horizontal plane of the support and rolling flanges.
 8. A city and/or district transport line particularly for passengers comprising: a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one shunting track connecting the halt track to the travel track; at least one car movable along the travel track and the halt track; first rolling means, carried by the car at a first vertical level thereof, for moving the car along the travel and halt tracks and for controlling the rate of movement of the car therealong, said first rolling means comprising: a first set of wheels rotatable on horizontal axes, said first set of wheels supporting the car on the travel and halt tracks and having driving means for advancing the car therealong, and a second set of wheels rotatable about vertical axes, said second set of wheels forming guiding means for guiding movement of the car along said travel and halt tracks; and second rolling means, carried by the car at a second vertical level thereof for engaging the shunting track to advance the car therealong and transfer the car from the travel track to the halt track of the intermediate station, the second rolling means being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track; said second rolling means comprising a third set of wheels rotatable about horizontal axes, said third set of wheels being engageable with a shunting track to advance the car between the travel and halt tracks.
 9. A transport line as defined in claim 8 wherein each car further comprises: a fourth set of wheels rotatable about vertical axes, said fourth set of wheels forming guiding means for guiding the car along the travel, halt, and shunting tracks.
 10. A city and/or district transport line particularly for passengers, comprising: a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of the line; at least one shunting track connecting the halt track to the travel track; at least one self-propelled car movable along the travel track and the halt track; a first set of wheels, carried by the car at a first vertical level thereof for supporting said car on said travel and halt tracks; controllable motor means on said car for driving the wheels of said first set to move the car along the travel and halt tracks and to control the rate of movement of the car therealong; and a second set of wheels, carried by the car at a second vertical level thereof for engaging the shunting track to rollingly support the car thereon and transfer the car from the travel track to the halt track of the intermediate station, the last mentioned wheels being movable from a retracted, rest position out of engagement with the shunting track to an extended, working position in engagement with the shunting track.
 11. A transport line as defined in claim 10 wherein: said shunting track slopes in a generally downward manner from connection with said travel track to connection with said halt track.
 12. A transport line as defined in claim 10 further comprising: a constant speed motor carried by said car for driving said second set of wheels.
 13. A city and/or district transport line particularly for passengers, comprising: a continuous travel track running without interruption between two terminal stations of the line; at least one halt track associated with an intermediate station of The line; at least one section of shunting track connecting each halt track to the travel track; at least one car movable along the travel, halt, and shunting tracks; first rolling means for the advancement of the car along the travel and halt tracks, said first rolling means being comprised of a first set of driven wheels rotatable about horizontal axes to support and advance the car, and a second set of wheels rotatable about vertical axes to guide the car, and second rolling means for advancing the car along the shunting track to transfer the car between the travel track and the halt track, said second rolling means being comprised of a third set of wheels including a pair of front wheels and a pair of rear wheels each rotatable about a horizontal axis and movable between a retracted, rest position not projecting beyond the lateral profile of the car and an extended, working position in engagement with the shunting track.
 14. A transport line as defined in claim 13 wherein: said third set of wheels is associated with a hydraulic control system for controlling the retraction and extension of the wheels.
 15. A transport line as defined in claim 13 wherein: the wheels of said third set idle about their respective axes, each car advancing by inertia along said shunting track.
 16. A transport line as defined in claim 15 wherein: each shunting track is arranged in a slightly descending path, the section of travel track lying beneath said shunting track being in turn arranged in a descending path of greater slope.
 17. A transport line as defined in claim 13 wherein: the wheels of said third set of wheels are driven through a transmission system operably associated with the first rolling means. 